Real-time monitoring of 3T3-L1 preadipocyte differentiation using a commercially available electric cell-substrate impedance sensor system
- Authors: Kramer, Adam H , Joos-Vandewalle, Julia , Edkins, Adrienne L , Frost, Carminita L , Prinsloo, Earl
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431171 , vital:72751 , xlink:href="https://doi.org/10.1016/j.bbrc.2013.12.123"
- Description: Real-time analysis offers multiple benefits over traditional end point assays. Here, we present a method of monitoring the optimisation of the growth and differentiation of murine 3T3-L1 preadipocytes to adipocytes using the commercially available ACEA xCELLigence Real-Time Cell Analyser Single Plate (RTCA SP) system. Our findings indicate that the ACEA xCELLigence RTCA SP can reproducibly monitor the primary morphological changes in pre- and post-confluent 3T3-L1 fibroblasts induced to differentiate using insulin, dexamethasone, 3-isobutyl-1-methylxanthine and rosiglitazone; and may be a viable primary method of screening compounds for adipogenic factors.
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- Date Issued: 2014
Selective modulation of plasmodial Hsp70s by small molecules with antimalarial activity
- Authors: Cockburn, Ingrid L , Boshoff, Aileen , Pesce, Eva-Rachele , Blatch, Gregory L
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431192 , vital:72752 , xlink:href="https://doi.org/10.1515/hsz-2014-0138"
- Description: Plasmodial heat shock protein 70 (Hsp70) chaperones represent a promising new class of antimalarial drug targets because of the important roles they play in the survival and pathogenesis of the malaria parasite Plasmodium falciparum. This study assessed a set of small molecules (lapachol, bromo-β-lapachona and malonganenones A, B and C) as potential modulators of two biologically important plasmodial Hsp70s, the parasite-resident PfHsp70-1 and the exported PfHsp70-x. Compounds of interest were assessed for modulatory effects on the steady-state basal and heat shock protein 40 (Hsp40)-stimulated ATPase activities of PfHsp70-1, PfHsp70-x and human Hsp70, as well as on the protein aggregation suppression activity of PfHsp70-x. The antimalarial marine alkaloid malonganenone A was of particular interest, as it was found to have limited cytotoxicity to mammalian cell lines and exhibited the desired properties of an effective plasmodial Hsp70 modulator. This compound was found to inhibit plasmodial and not human Hsp70 ATPase activity (Hsp40-stimulated), and hindered the aggregation suppression activity of PfHsp70-x. Furthermore, malonganenone A was shown to disrupt the interaction between PfHsp70-x and Hsp40. This is the first report to show that PfHsp70-x has chaperone activity, is stimulated by Hsp40 and can be specifically modulated by small molecule compounds.
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- Date Issued: 2014
Social entrepreneurship and employment creation in Zimbabwe: a case of Guruve rural district
- Authors: Munetsi, Rumbidzai
- Date: 2014
- Subjects: Social entrepreneurship -- Zimbabwe , Labor market -- Zimbabwe
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/26426 , vital:65307
- Description: In the last decade or so, social entrepreneurship has received a growing interest amongst researchers. Social entrepreneurship is the process of pursuing innovative solutions to social problems. The MDGs have formed the basis of commitment of the world leaders to reduce extreme poverty. As a result, the goals recognize specific development priorities across a very broad range such as poverty and education. They address targets such as increasing incomes; reduce hunger and achieving universal education. With the adoption of the ESAP in Zimbabwe, the government withdrew its support in the key areas of poverty reduction such as social services, education and agricultural inputs. This led to the destruction of livelihoods, marginalization of the poor and unemployment. Additionally, the government adopted the land reform programme in 2000. The programme affected the commercial farming and traditional source of exports which was a provider of 400 000 jobs for rural communities. The land reform precipitated the economic and subsequent social crisis in the country. Agricultural production was disrupted. The decline in the agricultural sector is correlated to the poverty levels in rural areas. The incidences of poverty are more pronounced in rural areas than urban areas. Poverty incidences are multi-faceted through various dimensions such as income levels, education and employment. Hence, the question is what can be done to address rural poverty? It is against this background that this study is determined to evaluate the impact of social entrepreneurship and poverty reduction in rural communities. Therefore the theoretical framework guiding this study is neo-liberalism theory, basic needs and sustainable livelihoods approach. , Thesis (MSoc Dev) -- Faculty of Management and Commerce, 2014
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- Date Issued: 2014
Spectral properties and photophysical behaviour of water soluble cationic Mg (II) and Al (III) phthalocyanines
- Authors: Idowu, Mopelola A I , Arslanoğlu, Yasin , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241549 , vital:50949 , xlink:href="https://doi.org/10.2478/s11532-013-0388-z"
- Description: Peripherally and non-peripherally tetrasubstituted-[(N-methyl-2-pyridylthio)]phthalocyaninato magnesium (II) (5 and 6) and chloro aluminium (III) (7 and 8) tetraiodide have been synthesized and characterized. The photophysical properties of the complexes in dimethyl sulfoxide (DMSO) and aqueous medium in the presence and absence of cremophore EL have been studied. These complexes show high solubility in aqueous medium though they were aggregated. The triplet state quantum yields (FT) and the triplet lifetimes (tT) were found to be higher in DMSO with ΦT ranging from 0.32 to 0.51, while tT ranged from 282 to 622 ms in DMSO, compared to aqueous medium (pH 7.4 buffer) where ΦT ranged from 0.15 to 0.19 and tT from 26 to 35 ms. Addition of cremophore EL in aqueous solution resulted in partial disaggregation and increased photoactivity. The fluorescence lifetimes of the complexes showed strong dependence on their immediate environment. The ionic magnesium(II) and aluminium(III) phthalocyanines strongly bind to bovine serum albumin (BSA).
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- Date Issued: 2014
Stable isotope evidence of food web connectivity by a top predatory fish (Argyrosomus japonicus: Sciaenidae: Teleostei) in the Kowie Estuary, South Africa
- Authors: Bergamino, Leandro , Dalu, Tatenda , Whitfield, Alan K , Carassou, Laure , Richoux, Nicole B
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457322 , vital:75625 , xlink:href="https://doi.org/10.2989/1814232X.2014.923782"
- Description: In this study, food web connectivity within the Kowie Estuary on the south-east coast of South Africa was evidenced by the trophic behaviour of the predominantly piscivorous Argyrosomus japonicus. We examined stable isotopes of carbon (δ13C) and nitrogen (δ15N) in the dominant consumers (zooplankton, invertebrates and fishes) and food sources (particulate organic matter, epibionts and benthic microalgae) in the system. An SIAR (Stable Isotope Analysis in R) mixing model was used to interpret the possible food sources for this dominant top predatory fish. Small fishes and large epibenthic invertebrates dominated the diet of A. japonicus. Based on the contrasting diet of these prey fish and invertebrates, we propose that organic matter enters the predatory fish community via two major pathways: (1) a littoral pathway dominated by benthic microalgae production and epibionts, and (2) a channel pathway dominated by suspended particulate organic matter (including phytoplankton). We conclude that the highly mobile A. japonicus consumes both pelagic and benthic fauna from the littoral and channel zones of the estuary, thereby playing a key functional role in linking food webs. This dietary diversity may help explain the success of A. japonicus as a dominant top predator in the system, primarily by increasing the energy available to this species.
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- Date Issued: 2014
Study South Africa
- Authors: International Education Association of South Africa (IEASA) , Jooste, Nico
- Date: 2014
- Subjects: Education, Higher -- South Africa , Education and globalization -- South Africa Student mobility -- Africa International education -- South Africa Education, Higher -- International cooperation , Universities and colleges -- South Africa , Technical Institutes -- South Africa , Vocational guidance -- South Africa
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/64864 , vital:28621 , ISBN 9780620620123
- Description: [Editor's Letter]: This 14th edition of Study South Africa foregrounds the celebration of 20 years of a democratic South Africa. Patrick Fish was commissioned to write a series of articles reflecting the development of South African Higher Education since 1994 for this edition. Reading through this the reader will hopefully experience a sense of the transformation of the South African Higher Education system. Although we all agree in South Africa that we are not done yet, we also recognise that given the South African realities, the change from a race based and fragmented system of higher education to a single but diverse system is well under way. The South African Universities transformed from mostly mono cultural to multicultural institutions that largely reflects the composition of the South African population. The University campuses also demonstrate the institutional appetite to be international. Not only do they jointly house more than 50,000 international students but are also involved in numerous ways in bringing the benefits of being globally connected to the local communities. We are one of the few higher education systems that largely fund our international activities from institutional budgets. This is one of the main reasons that South African Universities practice a style of internationalisation that is relevant to our institutional needs, as well as the local and national needs. Through our internationalisation endeavours we have connected with the rest of Africa in a very special way. Not only do we educate large numbers of students from other African countries but through the South African Higher Education alumni that now live all over the African continent we have built permanent connections that will enhance and develop long standing relationships. IEASA celebrates with all South Africans 20 years of democracy and realise that it is indeed a privilege to be practitioners in transformed ‘knowledge cities’. We are, however, saddened by the incidents of intolerance and destruction in other parts of the world that make the work of higher education institutions impossible, and can only in solidarity with those scholars at risk celebrate with deep appreciation the efforts and determination of those South Africans that made it possible for us to be Universities in a free and democratic society. , 14th Edition
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- Date Issued: 2014
Sustainability Assessment of University of Gondar, Gondar, North-west Ethiopia
- Authors: Moges, Haimanot G , Kifle, Desalegn W , Lotz-Sisitka, Heila , Woldyohhanes, Solomon M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182845 , vital:43885 , xlink:href="https://doi.org/10.1177/0973408214529990"
- Description: The purpose of this article is to provide an overview of the cross-institutional assessment of sustainable development practices in the University of Gondar (UoG). The focus of the assessment was the level of UoG academic departments’ integration of sustainability concerns in teaching, research and community service. Management contributions to sustainable development, student initiatives on sustainability issues and policy statements about sustainable development of UoG were also considered in the assessment. The data collection was based on the Unit-based Sustainability Assessment Tool (USAT); in addition, supplementary information was collected through observations across the four campuses of UoG from January to February 2012.The result of the assessment showed that only a few academic departments have incorporated sustainability concerns in their curricula and teaching approach. The initiation and commitment of academic departments in mainstreaming sustainability concerns in the research and community service delivered were relatively poor. The operation and management of UoG showed inadequate sustainable development practices on waste management, energy utilization and purchasing from environment-friendly companies. In addition, the written policy and statements of UoG did not reflect sustainability in an explicit manner. The university is expected to respond to the key themes defined through sustainability declarations on higher education; there is also a need to establish the relevance of these in relation to the systemic environment. From the study undertaken, we have learnt that sustainability assessment of universities using USAT will be more valuable, if universities have already initiated the embedding of sustainability so that USAT can be used to benchmark the continual improvement.
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- Date Issued: 2014
Synthesis and characterization of quantum dots designed for biomedical use
- Authors: Kuzyniak, Weronika , Adegoke, Oluwasesan , Sekhosana, Kutloano E , D'Souza, Sarah , Tshangana, Sesethu Charmaine , Hoffmann, Björn , Ermilov, Eugeny A , Nyokong, Tebello , Höpfner, Michael
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241516 , vital:50946 , xlink:href="https://doi.org/10.1016/j.ijpharm.2014.03.037"
- Description: Semiconductor quantum dots (QDs) have become promising nanoparticles for a wide variety of biomedical applications. However, the major drawback of QDs is their potential toxicity. Here, we determined possible cytotoxic effects of a set of QDs by systematic photophysical evaluation in vitro as well as in vivo. QDs were synthesized by the hydrothermal aqueous route with sizes in the range of 2.0–3.5 nm. Cytotoxic effects of QDs were studied in the human pancreatic carcinoid cell line BON. Cadmium telluride QDs with or without zinc sulfide shell and coated with 3-mercaptopropionic acid (MPA) were highly cytotoxic even at nanomolar concentrations. Capping with L-glutathione (GSH) or thioglycolic acid (TGA) reduced the cytotoxicity of cadmium telluride QDs and cadmium selenide QDs. Determination of the toxicity of QDs revealed IC50 values in the micromolar range. In vivo studies showed good tolerability of CdSe QDs with ZnS shell and GSH capping. We could demonstrate that QDs with ZnS shell and GSH capping exhibit low toxicity and good tolerability in cell models and living organisms. These QDs appear to be promising candidates for biomedical applications such as drug delivery for enhanced chemotherapy or targeted delivery of light sensitive substances for photodynamic therapy.
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- Date Issued: 2014
Synthesis and evaluation of novel heterocycles as potential HIV-1 enzyme inhibitors
- Authors: Ngnie Tuemgnie, Gaëlle Tatiana
- Date: 2014
- Subjects: Heterocyclic compounds , Enzyme inhibitors , Organic compounds , Green chemistry , Coumarins , HIV (Viruses) Enzymes
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194293 , vital:45440 , DOI https://doi.org/10.21504/10962/194293
- Description: This project has focussed on the synthesis and the evaluation of organic compounds as potential HIV-1 enzyme inhibitors, by making use of green chemistry (microwave assisted synthesis and click chemistry), palladium catalyzed reactions (Heck and Sonogashira coupling), Baylis Hillman methodology and aldol condensation. These compounds were synthesized in good yields and fully characterised by spectroscopic techniques. Biological assay data revealed that some of the compounds possess high inhibitory activity and their effective inhibitory concentration was as good as those of drugs in clinical use. These potential drug molecules were identified by preliminary investigations carried out by molecular modelling where a trend of their inhibitory activity against different enzymes was anticipated. Benzotriazole-AZT conjugates generated by 1,3-dipolar cycloaddition of anthranilic acid derivatives with AZT showed good inhibitory activity in silico against both HIV-1 protease (PR) and HIV-1 reverse transcriptase (RT) enzymes. Still in line with our dual action strategy, cinnamate ester-AZT conjugates were synthesized in three steps starting from benzaldehyde derivatives with a click reaction at the final step. These compounds also showed some inhibitory activity against HIV-1 RT enzyme (88%). In addition, the cinnamoyl fragment attached to AZT appeared to improve the activity of AZT against HIV-1 RT. Peptide chemistry involving carbonyl diimidazole as a coupling reagent between cinnamic acid derivatives and protected amino acids was used to prepare substituted amino acid derivatives which appeared to be very active against the integrase (IN) enzyme (88%). Commercially available coumarin was iodinated and derivatized through palladium catalyzed Heck and Sonogashira reactions with activated alkenes and a terminal alkyne respectively to afford novel coumarin derivatives in good yields. Optimization studies on the Heck reaction with regards to the phosphine ligand, the palladium catalyst and the solvent were carried out to afford novel formyl substituted cinnamate esters with nonaflyl salicylaldehyde derivatives. , Thesis (PhD) -- Faculty of Science, Chemistry, 2014
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- Date Issued: 2014
Synthesis and MRSA PK inhibitory activity of thiazole containing deoxytopsentin analogues
- Authors: Veale, Clinton G L , Lobb, Kevin A , Zoraghi, Roya , Morrison, James P , Reiner, Neil E , Andersen, Raymond J , Davies-Coleman, Michael T
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/448028 , vital:74692 , xlink:href="https://doi.org/10.1016/j.tet.2014.09.007"
- Description: The public health care crisis caused by the emergence of drug resistant bacterial strains, e.g., methicillin resistant Staphylococcus aureus (MRSA) has underlined the urgent need to accelerate the discovery of new chemical entities active against antibiotic resistant bacteria. We report here the synthesis of a series thiazole containing deoxytopsentin analogues, which show moderate activity against a target MRSA pyruvate kinase enzyme: an evolutionary conserved hub protein critical for bacterial survival. A Hantzsch thiazole coupling between a-oxo-1H-indole-3-thioacetamides and 2-bromo-1-(1H-indol-3-yl)-ethanones provided facile access to the thiazole containing deoxytopsentin compounds.
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- Date Issued: 2014
Synthesis of ytterbium bisphthalocyanines
- Authors: Sekhosana, Kutloano E , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189887 , vital:44943 , xlink:href="https://doi.org/10.1016/j.optmat.2014.05.013"
- Description: Herein we report on the syntheses, photophysico-chemical properties and nonlinear absorption parameters of bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-2-yloxy phthalocyaninato)} ytterbium (III) (3) and bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-4-yloxy phthalocyaninato)} ytterbium (III) (4). The fluorescence and singlet oxygen quantum yields obtained for complexes 3 and 4 are low. The triplet quantum yield obtained for complex 3 is high at ΦT = 0.89 whereas for complex 4 ΦT = 0.48. The third order optical susceptibility values are of the order: 10−11 esu (for complex 3), and 10−13 esu (for complex 4) while the hyperpolarizability values are of the order: 10−28 esu (for complex 3) and 10−31 esu (for complex 4). Complexes 3 and 4 show two-photon absorption coefficients of the order of 10−46 cm4 s/photon and 10−48 cm4 s/photon, and threshold intensities as low as 0.3 J cm−2 and 0.0045 J cm−2, respectively.
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- Date Issued: 2014
Synthesis, characterization & comparative evaluation of photo-catalytic & antimicrobial activity of Ag2O and TiO2 immobilized on nanofibres for treatment
- Authors: Gxumisa, Xoliswa
- Date: 2014
- Subjects: Pollution http://id.loc.gov/authorities/subjects/sh85104530 , Titanium dioxide http://id.loc.gov/authorities/subjects/sh85135627 , Photocatalysis http://id.loc.gov/authorities/subjects/sh93001301
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19545 , vital:43138
- Description: Water is a very essential substance for the existence of organisms and the environment where it functions as a transport medium for valuable chemicals, minerals, nutrients and also as a reaction medium. However, the remarkable water properties are not just limited to the dissolution of biological valuable substances, but also to harmful entities during pollution. This has led to research in the improvement and development of new techniques for water treatment. In this study, titanium dioxide (TiO2) and silver oxide (Ag2O) were prepared using the sol gel process and precipitation method respectively. The TiO2 was doped using a sol gel process with carbon and nitrogen so as to reduce the band gap. TiO2/Ag2O, N-TiO2/Ag2O and C-TiO2/Ag2O composites were also prepared using a precipitation method. The average particle size of prepared TiO2, C-TiO2, N-TiO2, Ag2O, TiO2/Ag2O, N-TiO2/Ag2O and CTiO2/Ag2O was found to be 13nm, 7nm, 10nm, 23nm, 28nm, 24nm and 21nm respectively as measured by TEM analysis. The photo-catalysts, Ag2O and TiO2 and their composites were immobilized on stabilized nanofibres using the electrospinning process to allow subsequent separation and reconciliation of the photo-catalyst after use in water treatment. The photocatalytic and antimicrobial activities of photo-catalysts were also evaluated using water contaminated with phenol red dye and Escherichia coli. The prepared materials were characterized by XRD, TEM, HRSEM, DRS, EDX, FT-IR, and TGA. Carbon was found to be more effective as a dopant than nitrogen. It reduced the band gap by 0.4 while nitrogen doping showed a reduction in band gap of 0.2 compared to undoped titanium dioxide. The doped TiO2 exhibited higher photo-catalytic and antimicrobial activity than the undoped TiO2. Introduction of Ag2O allowed utilization of visible light by the TiO2- Ag2O nano-composite leading to an improved rate of photo-degradation of phenol red and inactivation of E coli. Photo-catalytic properties showed that carbon doped materials have a higher photo-catalytic activity than nitrogen doped materials, while for antimicrobial v properties it is vice-versa. The immobilization of photo-catalysts on support material made it less effective towards the degradation of phenol red. The rate of photo-oxidation of phenol red was three times faster using powder TiO2 compared to immobilized TiO2. Therefore, this study suggests that photo-catalysis can be used as an effective method for water disinfection and production of potable and pathogen free drinking water even though better methods of immobilization should be sought. , Thesis (MSc) (Chemistry) -- University of Fort Hare, 2014
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- Date Issued: 2014
Synthesis, characterization and photodynamic therapy properties of an octa-4-tert-butylphenoxy-substituted phosphorus (V) triazatetrabenzcorrole
- Authors: Shi, Maohu , Tian, Jiangwei , Mkhize, Colin , Kubheka, Gugu , Zhou, Jinfeng , Mack, John , Nyokong, Tebello , Shen, Zhen
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241494 , vital:50944 , xlink:href="https://doi.org/10.1142/S1088424614500436"
- Description: A novel octa-4-tert-butylphenoxy-substituted phosphorus(V) triazatetrabenzcorrole (PVTBC), has been synthesized and characterized by MALDI-TOF MS and NMR, FT-IR and MCD spectroscopy. The fluorescence emission spectrum was used to determine the fluorescence quantum yield and the quantum yield for singlet oxygen generation was calculated by using 1,3-diphenylisobenzofuran as a scavenger. The photocytoxicity against U87MG cells was measured. The results indicated that PVTBC is potentially useful as an NIR region photosensitizer for photodynamic therapy (PDT).
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- Date Issued: 2014
Synthesis, photophysicochemical properties and TD-DFT calculations of tetrakis (2-benzoyl-4-chlorophenoxy) phthalocyanines
- Authors: Yilmaz, Yusuf , Mack, John , Sener, M Kasim , Sönmez, Mehmet , Nyokong, Tebello
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241538 , vital:50948 , xlink:href="https://doi.org/10.1142/S1088424614500047"
- Description: The synthesis of metal free, magnesium and zinc tetrakis(2-benzoyl-4-chlorophenoxy) phthalocyanine derivatives (2–4) is described along with their characterization by elemental analysis, IR, UV-visible absorption, and 1H NMR spectroscopy and mass spectrometry. Trends observed in the fluorescence, triplet state, singlet oxygen and photodegradation quantum yields and the triplet state lifetimes are also analyzed. The compounds exhibit high solubility in a wide range of organic solvents and no evidence of aggregation was observed over a wide concentration range. The Zn(II) complex (4) was found to have a very high singlet oxygen quantum yield (ΦΔ = 0.78) in dimethylsulfoxide (DMSO) and a reasonably large triplet state quantum yield (ΦT = 0.82). The photophysical and photochemical properties clearly demonstrate that these compounds could prove useful in singlet oxygen applications such as photodynamic therapy (PDT). DFT and TD-DFT calculations were used to assess the impact of the positional isomerism of the 2-benzoyl-4-chlorophenoxy substituents on the electronic structures and optical spectroscopy.
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- Date Issued: 2014
Temporal shifts in the fatty acid profiles of rocky intertidal invertebrates
- Authors: Richoux, Nicole B , Ndhlovu, Rachel T
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457336 , vital:75626 , xlink:href="https://doi.org/10.1007/s00227-014-2481-z"
- Description: Fatty acid profiles were determined in rocky intertidal suspension-feeders (mussels and polychaetes) and grazers (limpets and sea urchins) on a monthly basis over 1 year to assess potential dietary overlap between consumers occupying the same trophic guild, and any temporal shifts in diets. Both reproductive and non-reproductive tissues were assessed in an attempt to separate influences of food quality with those of life cycle. Relative variability in fatty acids over time could not be predicted from the feeding guild occupied by a consumer, and influential factors of the temporal shifts included both dietary and reproductive dynamics (even in muscle tissues). Species in the same trophic guild occupied separate trophic niches throughout the year, hence minimising competitive interactions regarding food acquisition. Based on overall variation in fatty acid profiles of muscle tissues, the suspension-feeders Perna perna and Gunnarea gaimardi and the grazing limpet Cymbula oculus occupied narrower feeding niches relative to the grazing sea urchin Parechinus angulosus. Our results provide compelling evidence for potentially large changes in the lipid composition of intertidal invertebrate populations over relatively small temporal scales (i.e. month to month), and these have important implications for short-term field collections intended for assessing invertebrate diets.
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- Date Issued: 2014
Thaumatotibia leucotreta and the Navel orange: ovipositional preferences and host susceptibility
- Authors: Love, C N , Hill, Martin P , Moore, Sean D
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423811 , vital:72095 , xlink:href="https://doi.org/10.1111/jen.12126"
- Description: False codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), presents a significant threat to the South African citrus industry. To limit income loss due to direct larval damage or from fruit rejection due to the phytosanitary status of this pest, additional pre-harvest control techniques are required for Navel oranges, which are known to be susceptible to T.leucotreta damage. A number of Navel orange cultivars have been developed, and differences in female T. leucotretaovi positional preference and susceptibility of cultivars to larval penetration are known to exist. Navel orange cultivars were grouped according to time of maturity (early, mid- and late season). Female T.leucotreta were subjected to choice and no-choice tests with these cultivars, measured by oviposition. Host susceptibility was tested by allowing neonate T. leucotreta larvae to penetrate the different Navel cultivars. In the early maturing group, Fischer Navels were least preferred for oviposition and the least susceptible to larval penetration. The mid- and late season maturing groupings showed limited differences in oviposition preference, although host susceptibility did appear to be an important factor in assessing the vulnerability of fruit to T. leucotreta. Despite being widely planted in South Africa, the mid-season Palmer Navels were highly susceptible to larval penetration, while for the late season cultivars, Cambria and Glen Ora Late were the least susceptible to T. leucotreta. As a result of these laboratory trials, it is recommended that farmers increase cultivation of Fischer Navels as the principal early season cultivar, avoid Palmer Navels in favour of other mid-season maturing cultivars and give preference to the late maturing Cambria and Glen Ora Late cultivars, to limit T. Leucotreta damage.
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- Date Issued: 2014
The challenges of re-skilling former prison inmates in the 21st century: a case study of Nkonkobe municipality, Eastern Cape - South Africa
- Authors: Ralasi, Nolusindiso
- Date: 2014
- Subjects: Criminals -- Rehabilitation , Prisoners -- Education , Alternatives to imprisonment
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25687 , vital:64432
- Description: The main aim of this study is to investigate challenges of re-skilling former inmates in South Africa in the 21st century. This is a case study of the Nkonkobe Municipality, Eastern Cape - South Africa. The objectives of this research are: to identify the current skills and education programmes offered by the DCS, to establish perceptions of inmates regarding the role of the DCS in skills training and education, to find out whether the current former inmates feel the support of society, to ascertain the offenders’ education levels, professional skills and job experience before and after prison, to identify the status of the offenders’ rights and rehabilitation programmes, to provide recommendations on ways to cement policy loopholes that have a deleterious effect on the government’s drive to create a whole new world for the ex-inmates and their holding communities. A qualitative research design was used to collect data from the participants in order to obtain in-depth information concerning the perceived impact of the life skills programmes on the behaviour and conduct of former inmates who participated in the programme. The findings reveal that the life skills programmes had an impact on the behaviour of former inmates because the life skills that they had gained from the programme mostly helped them desist from committing the offences that they used to commit. The life skills also curbed their anti-social behaviour tendencies. The factors that contributed to the success of the project included the approaches that the facilitators used to run the project, such as, motivating the inmates in everything that they did and the cooperation between the facilitators, the prison and the community. The findings also reveal that the good team work that occurred between the former inmates, support from the community, as well as the support from the Department of Correctional Services contributed to the success of the project. It was also suggested that the project should include all youths in the community; imprisonment should not be a passport to empowerment. The final suggestion was that the project should include all stakeholders in the community. The life skills projects should target unemployed youths in the communities so that they can gain skills that can help them become self-employed. The study also recommends that the life skills programmes should be implemented in all prisons in South Africa to provide inmates with life skills that can help them face day-to-day life challenges. This study culminates in the realisation that no life skills programmes can be successful in any society if they exclude the core social members who are law-abiding citizens. This is key to ensure that these programmes do not polarise the society due to empowerment being erroneously viewed as a preserve of those who did not abide by societal laws. This would set a wrong precedence that this study seeks to forestall. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2014
- Full Text:
- Date Issued: 2014
The comparative growth rates of indigenous street and garden trees in Grahamstown, South Africa
- Authors: De Lacy, Peter J G , Shackleton, Charlie M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180943 , vital:43672 , xlink:href="https://doi.org/10.1016/j.sajb.2014.02.007"
- Description: Urban forestry is advocated worldwide as a means of enhancing the liveability of towns and cities, and mitigating some of the anticipated impacts of climate change. Optimisation of the benefits of trees in urban areas is dependent upon knowledge of tree form, growth, and the products and benefits that trees provide. Growth rates are a vital variable for modelling benefits, yet there is a significant gap in knowledge pertaining to growth rates of trees in urban areas, especially indigenous species in developing world countries. Here we report on growth rates of indigenous street and garden trees in Grahamstown, South Africa, using two approaches; tree ring counts on increment cores and mean rates from trees of known planting age. Growth equations for both street and garden trees were derived. There was no significant difference in mean growth rates determined via the two methods. For both methods street trees grew approximately 30% slower than trees in gardens.
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- Date Issued: 2014
The effect of sap-sucking by Falconia intermedia (Hemiptera: Miridae) on the emission of volatile organic compounds from the leaves of Lantana camara varieties
- Authors: Heshula, Lelethu U P , Hill, Martin P
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406141 , vital:70242 , xlink:href="https://hdl.handle.net/10520/EJC150957"
- Description: Evidence from more than 100 plant species has confirmed that plants emit volatile organic chemicals (VOC) in response to herbivory (Karban and Baldwin 1997; Dicke et al. 2003; Arimura et al. 2005). Feeding-induced plant responses may result in higher levels of volatiles, and different bouquets of compounds being emitted by plants following herbivore damage (Wei et al. 2006). The emission of volatile chemicals may be beneficial to plants in two ways; undamaged plants may interpret the chemical signals from damaged plants and in turn prime themselves for defence (Arimura et al. 2000; Dicke et al. 2003; Agrawal 2005), or volatiles emitted by damaged plants may attract natural enemies of the herbivores, which may reduce further damage to the plants (Tumlinson et al. 1993; De Moraes et al. 1998; Dicke and Vet 1999).
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- Date Issued: 2014
The effects of extracellular and intracellular Hop on cell migration processes
- Authors: Contu, Lara
- Date: 2014
- Subjects: Heat shock proteins , Metastasis , Cancer Chemotherapy , Molecular chaperones , Cell migration
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193961 , vital:45410
- Description: The Hsp70/Hsp90-organising protein (Hop) is a 60 kDa co-chaperone that acts as an adaptor molecule, facilitating the transfer of client proteins between the Hsp70 and Hsp90 chaperone systems. Hop functions both intracellularly and extracellularly and has been implicated in many processes involved in cancer progression, including cell migration and invasion. Little is known about the mechanisms or domains by which extracellular Hop functions. In addition, little is known about the effects of Hop on signalling molecules involved in cell migration and invasion through regulation of actin dynamics. It was hypothesised that both extracellular and intracellular pools of Hop would regulate distinct cell migration processes by activation of cell signalling pathways or direct interactions with signalling intermediates. HS578T cells were treated with recombinant full length and truncated murine Hop proteins (overexpressed and purified in this study) to determine the effects of extracellular Hop and the independent domains on cell migration processes. Additionally, RNA interference (RNAi) techniques were used to determine the effect of Hop knockdown on cell migration related signalling intermediates and cell morphologies. A short hairpin RNA (shRNA) system for the stable knockdown of Hop was developed and used for a number of these studies. Treatment of HS578T cells with the TPR2A2B and TPR1 domains of Hop resulted in a significant decrease in cell migration and caused changes in the actin cytoskeleton and extracellular matrix proteins, gelatin and fibronectin. RhoC immunoprecipitated in a common complex with Hop and Hsp90. Hop knockdown reduced levels of actin and total RhoC, as well as active RhoC. In addition, knockdown of Hop resulted in a reduced migratory phenotype. We interpreted these data to indicate that intracellular Hop played a role in cell migration through regulation of RhoC activity, either through a direct interaction between Hop and RhoC, or an indirect interaction of RhoC with the Hsp90 multichaperone heterocomplex. Taken together, the data suggested that extracellular and intracellular Hop played distinct roles in extracellular and intracellular processes that lead to actin dynamics and cell migration. Understanding the mechanistic role of Hop in these processes is essential as it would aid in assessing the viability of Hop as a potential drug target for the treatment of metastatic cancers. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2014
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- Date Issued: 2014